Tulisa Contostavlos has been found guilty of assaulting a celebrity blogger at V Festival in Essex.

The N-Dubz star hit Savvas Morgan during a row in the VIP area at the site in Chelmsford last August.

She was found guilty by a judge at Stratford Magistrates' Court in east London and ordered to pay a total of £3,020.

Contostavlos shook her head and smiled in disbelief as the guilty verdict was read out.

Image Caption:Savvas Morgan rowed with Contostavlos at V Festival

She appeared to mutter "this is bulls**t" as she walked out of the courtroom.

The 26-year-old has vowed to launch an appeal against her conviction and said she was "outraged at the decision".

"There are a number of high-profile witnesses who were there and know what happened. I urge them to come forward and tell the truth at the appeal," she said outside the court.

"I am determined to clear my name as I have already done once this week. I repeat - I did not assault Vas J Morgan. I am innocent."

District Judge Angus Hamilton said he was "quite sure" based on the evidence that "Ms Contostavlos did strike Mr Morgan in the face during an argument and that that blow caused minor bruising and swelling".

He said Contostavlos acted in a "confrontational" manner when she turned towards her victim, who she reportedly held a grudge against after he included a link to her sex tape on his blog.

"Her decision to seek to deal with Mr Morgan herself strikes me as aggressive and confrontational," the judge said.

He went on to say that he had a "number of points of concern" about her evidence during the trial.

He found that she "changed her account" of what she did with her hands during the confrontation. At one point she claimed she raised them in a defensive gesture but later said they remained by her sides, he said.

Her assistant, Gareth Varey, was cleared of using threatening behaviour during the incident.

Jeremy Dein QC, barrister for Contostavlos, said in mitigation that his client was provoked by the actions of her victim in relation to the sex tape.

He told the court: "Mr Morgan played a significant part in humiliating and debasing Ms Contostavlos' reputation, clearly for financial gain."

Contostavlos must pay a £2,700 contribution towards the cost of the prosecution, a £200 fine, £100 compensation to Mr Morgan and a £20 victim surcharge.

Earlier this week, a drugs trial against Contostavlos collapsed at Southwark Crown Court after the judge said there were "strong grounds" to believe that undercover reporter Mazher Mahmood - known as the Fake Sheikh - had lied in the witness box.